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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3o4270

The halide shown has no hydrogen on the carbon next to the carbon bearing bromine. Select all correct statements.

  1. AE2 with sodium ethoxide is impossible because there is no beta-hydrogen.
  2. BSN2 is extremely slow because of steric hindrance at the carbon adjacent to the reaction centre.
  3. CIn hot ethanol a methyl shift accompanies ionisation to give a tertiary cation.
  4. DThe main product in hot ethanol is the unrearranged ethyl ether.

Answer: A, B, C

The compound is neopentyl bromide, in which the beta carbon is quaternary, so E2 cannot occur. The tert-butyl group blocks backside attack, making SN2 extremely slow. In hot ethanol ionisation is assisted by methyl migration to give the 2-methylbut-2-yl cation, which yields mainly 2-ethoxy-2-methylbutane and 2-methylbut-2-ene, so the unrearranged ether is not the main product.
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